Automatic trunking system.



0. V OLSON. AUTVOMAHC TRUNKiNG SYSTEM. APPLICATION FILED JUNE \2. 1909Patented Nov. 16, 1915 2 SHEETSSHEET I.

0. V. OLSON.

AUTOMATlC TRUNKlNG SYSTEM.

APPLICATION mzn JUNE 12 1909.

Patenfed Nov. 16,- 1915.

2 SHEETSSHEET 2.

[aa nn'r @FBTUB.

CKZ'O V. OLSON, OF CHICAGO, ILLINQIS, ASSIGNOB: TO AUTOMATIC ELECTRICCOMPANY, CF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TRUNKING SYSTEM.

To all whom it may concern:

Be it known that I, OTTO V. OLsoN, a citizen of the United States ofAmerica, and resident of Chicago, Cook county, Illinois, have invented acertain new and useful Improvement in Automatic Trunking Systems, ofwhich the following is a specification.'

My invention relates to automatic switchswitch and the shaft thereofagainst movement, whereby the switches will not be liable to give anyexcess motion by reason of momentum of the parts, and whereby they willnot be disturbed or displaced during use of the same for maintainingtalking connections, together with means for automatically unlocking thesaid master switch and shaft simultaneously with the energizing of themagnet by which the same are propelled or operated.

Another object is to provide improved means for maintaining the masterswitch in operation while traveling from one trunk terminal to another,so as to insure against stoppage of the master switch betweentrunks-that is to say, in passing from one trunk terminal to another.

A further object is to provide an improved constrtlction and arrangementwhereby the device for. insuring or maintaining the movement of themaster switch from one trunk to another serves also as a device forlocking the master switch whenever it comes 'to rest opposite the trunkline.

It is also an object to provide improved means for giving the callingsubscriber the busy signal in the event that all trunks to v which hisline switch has access are busy.

To the foregoing and other useful ends my invention consists in mattershereinafter set forth and claimed.

In the accompanying drawings Figure 1r is a diagram of an improvedmaster switch in a system embodying the principles of my invention. Fig.2 is a diagram showing an Specification of Letters Patent.

Patented Nov. is, rare.

Application filed June 12, 1909. Serial No. 501,718.

automatic two-wire substation connected with the central station,showing the line switch, the said master switch and a selector.

The master switch, as represented in detail in Fig. 1, comprises themotor magnet 2 adapted to operate' the ratchet wheel 3, which in turnoperates the plunger shaft 4 through the medium of the arm 5 andconnecting shaft 9. The master switch bank Q consists of ten insulatedcontacts a and the solid segment 6. The wiper 6 maintains someone of theindividual segments a in contact with the common segment I). The

motor magnet relay 7 closes an energizing circuit through the motormagnet 2. The motor magnet relay is in turn energized by the busy trunkrelay 8. At the top of the connecting shaft 9 is a spacing cam orsegment 10 adapted to move back and forth having on its are ten circularopenings adapted to fit the pin 11 at the extremity of the armature 12of the motor magnet relay 7 This spacing cam 10 is fastened tothe shaft9 and rotates with it.

When a trunk upon which is resting the wiper 6 is seized (in thisinstance 0) ground is then thrown upon the common segment I) from thetrunk 0 through the wiper 6, thence by means of conductor 15 through thebusy relay 8 to the negative side of battery B. i

The relay 8 energizes and brings the springs 13 and 14 into contactwhich, by closing another circuit, energizes the motor magnet relay 7.This circuit extends from ground G through the springs 13 and 14, motormagnet relay 7 to battery B, thence through battery B to ground G. Thearmature 12 is thus operated, and the finger 11 withdrawn from theparticular opening in the cam 10 in which it happens to be normallyresting at the time Also, at the same time the springs 16 and 17 areclosed by-the operation of said armature, completing an energizingcircuit from ground G through the motor magnet 2, interrupter springs 19and 18, springs 17 and 16 to battery B, thence through battery B toground G. The motor magnet2, upon energizing, draws up the armature 20,causing the pawl 21to engage the ratchet wheel 3 and rotate it at thesame time that the the'springs 16 and 1?.

lar to that of a buzzer, thus giving the ratchet wheel 3 a continualrotary motion as long as the spring 16 engages the spring 17-. When themotor magnet relay 7 deenergizes,

5 the armature 12 will not fall back to normal 5 shaft'come's to restall the plungers engag- -ins it are opposite a particular trunk linecorresponding to the aperture occupied by the armature finger .1. Theshaft isthereby locked and cannot be changed in position 20 until: therelay 7 is again energized. At the I time that the spring 16 breakscontact with the spring 7 2 and closes with the spring 17, the spring 94engages the spring 72, closing a circuit which gives the busy signal toa subscriber if all ten trunks are engaged, as

willbe described later.

' The substation A. of Fig. 2 may be of any suitable or approved type.In this instance t comprises the usual receiver 22, switch 3, hook 223,induction coil Qtwhich consists of the primary winding 25 and secondarywinding 26, transmitter 27, condenser 28, ringer 29., and impulse wheelwith the usual impulse teeth 31. The impulse wheel 30 is secured to theshaft 32, to which there is also secured the dial not shown). "When thedial is turned theimpulse teeth 31 are. adapted to engage the cam 33upon the end of the spring 34 and thereby carrythe latter out of engagemnt with the spring 35.

Upon the switch book 23 is secured the cam 36 which, when the swi chhook 18 up, pernuts the springs 37 am 38 to engage, thereby bridgingacross the subscribers line con ductors 39 and 40 the primary circuitincluding the transmitter 27 in series with the primary winding b5.When, however, the switch hook is lowered the spring 37 is carried outof engagem nt with the spring 38 and into engagement with the spring 41,

whereby the ringer, 29 in series with the corn denser 28 is bridgedacross the line conductors 39 and 40 instead.

The line switch C (Fig. 2) .is a modified form of that described inBritish Letters Patent No. 26,301 of 1806.

001i 412 with three windings 4,6, 44: and 45 it comprises th which maybe designated as the trip wind mg, the line relay winding and thebridgecut-oil? winding, respectively.- The brides cut-off armature 46,when operated, shifts the springs and 48 out of engagement with thesprings 47 and 50, respectively. The first selector switch "E is of thegen- 65 eral type described in United States Letters may be designatedas the vertical, rotary and private side switch wipers, the rotarymagnet wiper and the bridge-cut-otl' wiper,

respectively. The side switch is under the control of the private magnet59; and the 'windings of the usual vertical and rotary line relays are,in this case, combined in one v double-wound relay 60 comprising onewinding 61 connected with the battery lead 74,

and also with the vertical trunk line conductor, when the side switchwiper 54 is in first or second position. The second winding 62 isconnected to ground, and also to the rotary trunk line' conductor, whenthe side switch wiper 55 is in first or second positicn. Through'themedium of this doublewound relay, and while the side switch is in firstposition, the subscriber controls the vertical magnet 68 which operatesto raise the switch shaft and wipers 51, 52 and 53. The line relay 60also controls the private magnet relay 63, which latter in turn controlsthe private magnet 59. While the side switch is in second position therotary mag net 64, which operates to give the switch shaft and'wipers arotary movement, is energized. The release magnet 65 provides means forrestoring the selector switch to normal position. Upon the switch shaftwhich carries the wipers 51, 52 and 53there is mounted the arm 66 which,when the shaft is raised one or more steps, permits the lOO spring 67 toengage the contact point 68,

whereby the release magnet 65 is connected to the battery lead. Therelease relay 69 is provided for closing the energizing circuit of therelease magnet 65 after the switch is operated Furthermore, the relay69, upon energizing, provides an energizing circuit for the cut-offrelay winding of the line switch to maintain the latter in its 0peratedposition.

The operation of the master switch O may across the line an energizingcircuit is completed for the line relay winding 4 1*, said e betterunderstood by showing at whatand 81, and 82 and 83.

circuit extending from ground G through the springs 47 and 7 O to theline conductor 40, through the primary circuit of the substation to theline conductor 39, through the springs 50 andt48, winding 44, springs 72and 16 to battery B, thence through battery B to ground G. The .rclaywinding 44, upon energizing,- attracts the armature 73 and therebycloses contact between the springs 47 and-49. hen this occurs anenergizing circuit is established through the trip-in winding 43 of thecoil 42. This circuit extends from ground G through the springs 47 and49, trip-in winding 43 to the contact point 712, spring 16, to thebattery lead 74, thence through battery B to ground G. On becomingenergized the winding 43 attracts the armature 46 and the plunger arm75. The armature 46 acts to separate the springs and 48 from the springs47 and 50, respectively, disconnecting the line conductors 40 and 39from the line switch coils. The plunger arm 75 serves to thrust theplunger (not shown) into the bank terminal of an idle trunk. pressingthe bank springs into contact said springs represented in Fig. 2 bysprings 76 and 77, 78 and 79, 80 The engagement of the springs 76 and 77and 82 and 83 extends the subscribers line conductors 39 and 40,respectively, to the line relay 60 of the first selector switch E. VVhenthe bank springs 80 and 81 engage, an energizing circuit is establishedthrough the busy trunk relay over the trunk 0 from ground G whichresults in the operation of the master switch, as hereinbeforedescribed, to carry the wiper 6 to the next non-grounded contact. Untilthe lineswitch has been released, and the master switch returns to theoriginal position from which the plunger was released, the operation ofthe line switch or of the instrument A in no way affects the masterswitch. The subscriber at substation A proceeds to rotate his dial andmake his call in the regular manner, operating the first seductor 39,through the bank springs 76 and 77, conductor 85, through the sideswitch wiper 54, winding 61 of the line relay 60 to the battery lead 74,thence through battery B to ground G. The line relay 60 is energized andseparates the spring 86 from the spring 87 and places-it in contact withthe spring 88. A circuit is thus closed through the releasing relay 69,said circuit extending from ground G through the springs.86 and 88,relay 69 to the battery lead 74, thence through battery B to ground G.The releasing relay, in energizing, closes contact between the springs89 and 90, thereby completing a circuitfrom ground G through the sideswitch wiper 58, springs 90 and 8 banksprings 79 and 78, through thebridge-cut-ofl' winding 45 of the line switch coil 42 to the batterylead 74,thence through battery B to ground G. This circuit is maintainedas long as the receiver is off the hook, ground being obtained at Gthrough the side switch wiper 58 in the first and second positions. andover the release trunk 91. when the side switch is in third position.-The winding 45 of the coil 42 holdsdown the armature 75 and retains theplunger in the bank until the connection is released. hen the receiveris returned to the hook, ground is removed from the release trunk 91 bythe release of the switch succeeding the selector E, Consequently, thereleasingrelay 69 de'e'nergizes and closes a circuit through the releasemagnet 65.as. follows: From ground Gr through the line relay springs 86and 87, springs 92 and 93, release magnet 65, contact point 68, spring67 to the battery lead 74, thence through battery B to ground G. Thearmature of the release magnet, pulling up, restores the side switch andshaft to their normal positions. As the shaft drops to its originalposition the finger 66 of the shaft breaks the contact between thecontact point 68 and, the spring 67 and allows the release magnet todeenergize. \Vhen the releasing relay 69 denergizes, the circuitthroughthebridge-cutotf coil 45 is broken by the separation of thesprings 89 and 90. The bridge-cut-off winding deenergizes, allowing thespiral spring 95 acting upon the arm 75 to withdraw the plunger from thebank. The bank springs thus separate, and ground is'removed from thetrunk c (by the" separation of the springs 80 and 81) leading to themaster switch bank contact upon which the wiper 6 was resting justprevious to the call. The trunk lines corresponding to this contact 'arenow free to be seized by the same or an other subscriber as shon as themaster switch in its rotation brings the plungers again over said trunk.If all the ten trunks 0 of the master switch bank are grounded, as willbe the case when all the trunks from the line switch banks are engaged,the master switch will continue to rotate until some trunk isdisengaged; Should a subscriber attempt to makea call at this time hewill trunk relay 8, which is energized as long as the master switchwiper continues, to

engage busy trunks. Consequently, the

springs 72 and 9 will remain in contact, and the spring 16 will continueseparated from the spring 72 and in contact with the spring 17 The lineswitchof the subscriber will, therefore, not be operated, since batterycurrent is cut off from the line by the separation of the springs 72andltl. A circuit will then be maintained from the line conductor 39through the springs 50 and 48, line relay winding 4 springs 72 and 94,condenser 100, secondary winding 96 of the transformer 97 to the batterylead 74, thence 51 and 52 to the next switch, the line relay and releaserelay of that switch operate to ground the private bank contact on whichthe wiper 53 is resting in the same manner in .which the first selectorE grounds the bank contact 79 when the line switch C is operated.

From the the means consisting of the apertured segment l0 and therelay-controlled locking pin 11 constitute a device for not only lookingthe master switch while it is at rest, but also for maintaining themotion of the master switch while passing from one trunk to another.This device also governs the means for giving the. busy signal to thecalling subscriber in the event that all of the trunks to which his lineswitch has access are busy. If a subscriber calls whenthe master switchis in motion he receives the busy signal, in the manner explained.

It will also be seen that my invention is disclosed in connection with asystem of that character in which the subscribers are divided intogroups, and in which connectors may be employed having vertical motionto select groups, and then rotary motion to find the called line in anyselected group. Each group may be made up of ten subscribers, and thetenv levels constitute the larger group of one hundred subscribers. Thetrunks are also divided into groups, so that the selectors have verticalmotion to selectgroups, and then rotary motion. to find an idle trunk inany selected group. It will be understood that this principle oftrunking can be carriedout to any desired extent as by using first andsecond selectors, oreven third and fourth and other selectors, dependingupon the size or ultimate capacity of the exchange.

foregoing it will be seen that inecgeai lVhat I claim as my invention isi. in a telephone system, a line-switchgoverning master switch provided.with automatic means for positively locking the same against motionwhile at rest, and

said device, and automatic means whereby the said device when unlockedmaintains the circuit of said magnet closed at one point to insure theoperation of the master switch.

4. In a telephone system, a line-switchgoverning master switch providedwith a propelling magnet, and means including a back and forth operatingor swinging member provided with openings and contacts controlledthereby whereby the energizing of the said magnet is interrupted atintervals, and the master switch positively locked against motion whileat rest.

5. In a telephone system, a line-switchgoverningmaster switch providedwith a propelling magnet, a relay controlling said magnet, a deviceoperated by the master switch to mechanically control the operation ofsaid relay, and another relay controllin said first-mentioned relay. V e

6. In a telephone system, a line-switchgoverning master switch providedwith a propelling magnet, a relay controlling said magnet, said relayhaving an armature, a device operated by the master switchand'cooperating withsaid armature to govern the energizing of saidmagnet, and means controlling the energizing of said relay.

7. In a telephone system, a line switchgoverning master switch providedwith a re lay having normally open contacts, and a busy signalcontrolled by said contacts, whereby a calling subscriber will receivethe busy signal it the call is made while the said contacts are closed.

8. In a telephone system, a line-switchgoverning master switch providedwith a relay controlling the operations thereof, a device operated bythe master switch to govern the control exercised by said relay over themaster switch, and automatic means controlled by said relay forgivingthe calling subscriber the busy signal if the call is made forcontrolling the circuit of said magnet, an

arc-shaped rack operated by the movement of said switch having aplurality of openings corresponding to the various positions of saidswitch, and means controlled by said rack to control tli circuit of saidoperating magnet so as to insure the proper operation of said switch.

11. In a telephone system, a plurality of switches, trunks associated"with said switches, a master switch provided with automatic meanscomprising a magnet for locating an idle trunk, a relay for controllingthe circuit of said aut matic means independent oi? 12mintaining thecircuit oi: sale iii-agnet closed at one point to insure the properoperation of the switch.

12. In a telephone system, switches, trunks associated switches, amaster switch tomatic means comprising; eating an idle trunk, a relaythe circuit of said means operated by said swiw trolling the circuit ofsaid ma the operation of said switch.

Signed by me at Chicago, woo county, 325 Illinois, this 24. day of May,1909.

' @TTG 3 bLSQli.

Witnesses:

ARTHUR J. RAE, EDWARD D. hams.

